title: Commentary on "Plasma carotenoids and vitamin C concentrations and risk of urothelial cell carcinoma in the European Prospective Investigation into Cancer and Nutrition." Ros MM, Bueno de Mesquita HB, Kampman E, Aben KK, Büchner FL, Jansen EH, van Gils CH, Egevad L, Overvad K, Tjønneland A, Roswall N, Boutron Ruault MC, Kvaskoff M, Perquier F, Kaaks R, Chang Claude J, Weikert S, Boeing H, Trichopoulou A, Lagiou P, Dilis V, Palli D, Pala V, Sacerdote C, Tumino R, Panico S, Peeters PH, Gram IT, Skeie G, Huerta JM, Barricarte A, Quirós JR, Sánchez MJ, Buckland G, Larrañaga N, Ehrnström R, Wallström P, Ljungberg B, Hallmans G, Key TJ, Allen NE, Khaw KT, Wareham N, Brennan P, Riboli E, Kiemeney LA, National Institute for Public Health and the Environment, Bilthoven, Netherlands: Am J Clin Nutr 2012;96(4):902-10 [Epub 2012 Sep 5].
abstract: BACKGROUND
  Published associations between dietary carotenoids and vitamin C and bladder cancer risk are inconsistent. Biomarkers may provide more accurate measures of nutrient status.
  
  
  OBJECTIVE
  We investigated the association between plasma carotenoids and vitamin C and risk of urothelial cell carcinoma (UCC) in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition.
  
  
  METHODS
  A total of 856 patients with newly diagnosed UCC were matched with 856 cohort members by sex, age at baseline, study center, date and time of blood collection, and fasting status. Plasma carotenoids (α- and β-carotene, β-cryptoxanthin, lycopene, lutein, and zeaxanthin) were measured by using reverse-phase HPLC, and plasma vitamin C was measured by using a colorimetric assay. Incidence rate ratios (IRRs) were estimated by using conditional logistic regression with adjustment for smoking status, duration, and intensity.
  
  
  RESULTS
  UCC risk decreased with higher concentrations of the sum of plasma carotenoids (IRR for the highest compared with the lowest quartile: 0.64; 95% CI: 0.44, 0.93; P-trend = 0.04). Plasma β-carotene was inversely associated with aggressive UCC (IRR: 0.51; 95% CI: 0.30, 0.88; P-trend = 0.02). Plasma lutein was inversely associated with risk of nonaggressive UCC (IRR: 0.56; 95% CI: 0.32, 0.98; P-trend = 0.05). No association was observed between plasma vitamin C and risk of UCC.
  
  
  CONCLUSIONS
  Although residual confounding by smoking or other factors cannot be excluded, higher concentrations of plasma carotenoids may reduce risk of UCC, in particular aggressive UCC. Plasma lutein may reduce risk of nonaggressive UCC.
authors.forename: William A
authors.initials: WA
authors.lastname: See
mesh_terms: D001205:Ascorbic Acid / Q000097:blood*; D002295:Carcinoma, Transitional Cell / Q000097:blood*; D002338:Carotenoids / Q000097:blood*; D004032:Diet; D005260:Female; D006801:Humans; D008297:Male; D001749:Urinary Bladder Neoplasms / Q000097:blood*; D019459:Urothelium / Q000473:pathology*
chemical_list: D002338:Carotenoids; D001205:Ascorbic Acid